I think it's incredibly unintelligent to say "Years from now, people will love this" or "They all laughed at Christopher Columbus (or the St. Louis Arch), and they were wrong...
therefore, if you are critical of something now, you must be wrong too." Both of those statements are great examples of fallacious reasoning.
No one knows how the Arch d'IKEA is going to be thought of in 10, 20 or 50 years. Maybe people will love it or maybe it will be a laughingstock --
nobody knows, so why use that as an argument??? It would be just as silly to say "Gee, it looks great now, but in the future, people are going to hate it."
Of course, you can think that, but do you really think that's an
argument?
The other argument, comparing it to the St Louis Arch, is even worse. It assumes that somehow the two edifices are somehow similar in some significant respect and thus public reaction to them will be similar. They are different edifices, we are different publics, one is genuinely original (whether you like it or not--I happen to) and the other is a hoary imitation of much-better known (and genuinely monumental) monuments. Why would anyone even compare them? Why not compare a WalMart to the Taj Mahal? They both occupy space...